The effect of systemic and topical ophthalmic medications on choroidal thickness: a review

The choroid plays an important role in various ocular pathologies and retinal blood supply. There is a knowledge gap on how the choroid is affected by systemic and topical medications. Systemic medications that affect microvasculature elsewhere in the body can also affect the microvasculature of the choroid. This review summarizes current knowledge on associations between systemic and topical medications and changes in choroidal thickness (CT). This review included 71 studies on mydriatics/cycloplegics, intraocular pressure (IOP)-lowering therapies, antihypertensives, adrenergic antagonists, statins, corticosteroids, hydroxychloroquine, isotretinoin, hormonal contraceptives, phosphodiesterase inhibitors, antipsychotics, antineoplastic agents, ethanol, caffeine and nicotine. IOP-lowering therapies, atropine eye drops, and systemic administration of β blockers and ethanol are associated with a significant increase in CT. Cyclopentolate and phenylephrine are associated with a CT reduction. Systemic medications that decrease CT include caffeine and nicotine. Tropicamide, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, statins, corticosteroids, hydroxychloroquine and hormonal contraceptives have mixed findings. CT increase associated with IOP-lowering therapies is possibly achieved by enhancing aqueous humour flow to the choroid thus elevating choroidal blood flow and thickness. CT changes appear to be independent from systemic blood pressure changes, suggesting that a significant association with an antihypertensive could be due to an idiosyncratic drug property. Statins and candesartan decrease macrophage accumulation and intercellular adhesion molecule 1 expression in the choroid. The choroid and its response to various disease processes and systemic medication can be further investigated to improve patient care, particularly in patients with choroid and retina pathologies.